All error codes

disk_not_extendable

HTTP 422 This disk cannot be resized

What happened

The platform refused to resize the addressed disk because it is not a data disk. In practice the server's disk list contains only data disks and the system disk, so a slot outside that set answers disk_not_found first and this code is rare."

What to do

Address a data disk instead, or change the server's disk_gb if you meant the system disk. The disk list shows which disks are resizable.

Retrying

Fix the request and send it again.

How it arrives

{
    "type": "https://docs.fiberax.com/errors/disk_not_extendable",
    "title": "This disk cannot be resized",
    "status": 422,
    "code": "disk_not_extendable",
    "request_id": "a277dcd1ca652c65"
}

Branch your code on code, never on the wording of title.